Conductive Polymer Electrolyte for Stable Capacitor ESR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrolytic capacitors face a challenge in maintaining low Equivalent Series Resistance (ESR) over time due to the de-doping phenomenon, where the conductive polymer dopant is released, especially under high-frequency applications that generate heat, causing pH increase and ESR changes.
Innovation Solution
An electrolytic capacitor design featuring a conductive polymer with a second polymer acid component as a dopant, combined with a liquid component containing a first polymer acid component with sulfonic or carboxylic acid groups, which suppresses de-doping and esterification reactions, maintaining stable ESR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive polymer with dopant is used as solid electrolyte layer, then large electrostatic capacitance and low ESR are achieved, but the dopant is gradually released from the conductive polymer in electrolytic solution causing ESR to increase over time
Solution Approach 1:
The patent introduces a polymer-coated sulfonic acid component as an intermediary substance between the conductive polymer and the electrolytic solution. This intermediary suppresses the de-doping phenomenon by preventing direct interaction that would cause dopant release, while still allowing the conductive polymer to maintain its low ESR properties. The polymer coating on the sulfonic acid component acts as a controlled interface that protects the dopant.
Solution Approach 2:
The patent changes the chemical parameters of the electrolytic solution by using a polymer acid component with specific molecular weight (10,000-1,000,000) and specific acid groups (sulfonic or carboxylic). This parameter change transforms the electrolytic solution from one that causes rapid de-doping to one that suppresses dopant release while maintaining capacitor performance.
2Speed
If high frequency is applied to the electrolytic capacitor, then power delivery is improved, but heat is generated causing pH increase and esterification of monomolecular sulfonic acid
Solution Approach 1:
The patent converts the harmful effect of heat generation into a beneficial outcome. By using a polymer acid component instead of monomolecular sulfonic acid, the heat that would normally cause esterification and pH increase is transformed into an acceptable condition that does not degrade the capacitor. The polymer structure resists esterification even at elevated temperatures, turning the heat problem into a non-issue.
Solution Approach 2:
The patent uses a composite acid component consisting of polymer backbone with sulfonic or carboxylic acid groups. This composite material combines the beneficial pH-buffering capacity of sulfonic acids with the thermal stability of polymer structures, allowing the capacitor to handle high-frequency power delivery without suffering from heat-induced degradation.
3Reliability
If monomolecular sulfonic acid is used in electrolytic solution, then de-doping phenomenon is suppressed, but esterification occurs at high temperature causing pH increase and reduced long-term stability
Solution Approach 1:
The patent replaces monomolecular sulfonic acid with a polymer acid component having molecular weight of 10,000-1,000,000. This composite material maintains the de-doping suppression capability of sulfonic acids while adding thermal stability through the polymer structure. The polymer backbone prevents esterification reactions that would otherwise occur with monomolecular acids at elevated temperatures.
Solution Approach 2:
The patent changes the molecular weight parameter of the acid component from monomolecular scale to polymer scale (10,000-1,000,000). This parameter change fundamentally alters the chemical behavior, suppressing both de-doping and esterification while maintaining pH stability under high-temperature operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents ESR degradation by reducing dopant release and pH increase, ensuring long-term stability and consistent performance even under high-temperature conditions.
Implementation Method 1
During use of an electrolytic capacitor, the Equivalent Series Resistance (ESR) of the electrolytic capacitor may gradually increase. This is probably caused due to the dopant gradually released from the conductive polymer in an electrolytic solution (a de-doping phenomenon).
Implementation Method 2
When, however, the electrolytic capacitor is used, for example, in such a state where a high frequency is applied to the electrolytic capacitor, the electrolytic capacitor may generate heat, and the heat may esterify monomolecular sulfonic acid, so that the pH of the electrolytic solution may increase.
Data Source
AI summary
An electrolytic capacitor according to the present disclosure includes an anode body, a cathode body, a solid electrolyte, and a liquid component. The anode body has a surface provided with a dielectric layer. The solid electrolyte is in contact with the dielectric layer, is disposed between the anode body and the cathode body and contains conductive polymer. The liquid component is in contact with the dielectric layer and the solid electrolyte and contains a solvent and an acid component. The acid component contains a first polymer acid component including a sulfonic acid group or a carboxylic acid group.